Version bump to 2.4.0

Previously, the Faraday testing adapter compared the request body to the
stubbed body just by calling `#==` if the stubbed body is present.
Sometimes, I want to check the equality between request and stubbed body
in more advanced ways. For example, there is a case that I want to check
only the parts of the body are actually passed to Faraday instance like
this:

```ruby
stubs = Faraday::Adapter::Test::Stubs.new do |stub|
  stub.post('/foo', '{"name:"YK","created_at":"ANY STRING IS OK"}') { [200, {}, ''] }
end
connection.post('/foo', JSON.dump(name: 'YK', created_at: Time.now))
stubs.verify_stubbed_calls
```

In this case, it's difficult to make tests always pass with
`"created_at"` because the value is dynamic. So, I came up with an idea
to pass a proc as a stubbed value and compare bodies, inside the proc:

```ruby
stubs = Faraday::Adapter::Test::Stubs.new do |stub|
  check = -> (request_body) { JSON.parse(request_body).slice('name') == { 'name' => 'YK' } }
  stub.post('/foo', check) { [200, {}, ''] }
end
connection.post('/foo', JSON.dump(name: 'YK', created_at: Time.now))
stubs.verify_stubbed_calls
```

I believe this would be flexible but compatible with the previous behavior.

docs/adapters/testing.md

@@ -64,6 +64,14 @@ initialized. This is useful for testing.
 stubs.get('/uni') { |env| [ 200, {}, 'urchin' ]}
 ```
 
+You can also stub the request body with a string or a proc.
+It would be useful to pass a proc if it's OK only to check the parts of the request body are passed.
+
+```ruby
+stubs.post('/kohada', 'where=sea&temperature=24') { |env| [ 200, {}, 'spotted gizzard shad' ]}
+stubs.post('/anago', -> (request_body) { JSON.parse(request_body).slice('name') == { 'name' => 'Wakamoto' } }) { |env| [200, {}, 'conger eel'] }
+```
+
 If you want to stub requests that exactly match a path, parameters, and headers,
 `strict_mode` would be useful.
 

examples/client_spec.rb

@@ -17,6 +17,11 @@ class Client
     data = JSON.parse(res.body)
     data['origin']
   end
+
+  def foo(params)
+    res = @conn.post('/foo', JSON.dump(params))
+    res.status
+  end
 end
 
 RSpec.describe Client do
@@ -94,4 +99,21 @@ RSpec.describe Client do
       stubs.verify_stubbed_calls
     end
   end
+
+  context 'When you want to test the body, you can use a proc as well as string' do
+    it 'tests with a string' do
+      stubs.post('/foo', '{"name":"YK"}') { [200, {}, ''] }
+
+      expect(client.foo(name: 'YK')).to eq 200
+      stubs.verify_stubbed_calls
+    end
+
+    it 'tests with a proc' do
+      check = ->(request_body) { JSON.parse(request_body).slice('name') == { 'name' => 'YK' } }
+      stubs.post('/foo', check) { [200, {}, ''] }
+
+      expect(client.foo(name: 'YK', created_at: Time.now)).to eq 200
+      stubs.verify_stubbed_calls
+    end
+  end
 end

examples/client_test.rb

@@ -18,6 +18,11 @@ class Client
     data = JSON.parse(res.body)
     data['origin']
   end
+
+  def foo(params)
+    res = @conn.post('/foo', JSON.dump(params))
+    res.status
+  end
 end
 
 # Example API client test
@@ -109,6 +114,27 @@ class ClientTest < Test::Unit::TestCase
     stubs.verify_stubbed_calls
   end
 
+  def test_with_string_body
+    stubs = Faraday::Adapter::Test::Stubs.new do |stub|
+      stub.post('/foo', '{"name":"YK"}') { [200, {}, ''] }
+    end
+    cli = client(stubs)
+    assert_equal 200, cli.foo(name: 'YK')
+
+    stubs.verify_stubbed_calls
+  end
+
+  def test_with_proc_body
+    stubs = Faraday::Adapter::Test::Stubs.new do |stub|
+      check = ->(request_body) { JSON.parse(request_body).slice('name') == { 'name' => 'YK' } }
+      stub.post('/foo', check) { [200, {}, ''] }
+    end
+    cli = client(stubs)
+    assert_equal 200, cli.foo(name: 'YK', created_at: Time.now)
+
+    stubs.verify_stubbed_calls
+  end
+
   def client(stubs)
     conn = Faraday.new do |builder|
       builder.adapter :test, stubs

lib/faraday/adapter/test.rb

@@ -26,6 +26,15 @@ module Faraday
     #         ]
     #       end
     #
+    #      # Test the request body is the same as the stubbed body
+    #      stub.post('/bar', 'name=YK&word=call') { [200, {}, ''] }
+    #
+    #      # You can pass a proc as a stubbed body and check the request body in your way.
+    #      # In this case, the proc should return true or false.
+    #      stub.post('/foo', ->(request_body) do
+    #        JSON.parse(request_body).slice('name') == { 'name' => 'YK' } }) { [200, {}, '']
+    #      end
+    #
     #       # You can set strict_mode to exactly match the stubbed requests.
     #       stub.strict_mode = true
     #     end
@@ -42,6 +51,12 @@ module Faraday
     #
     #   resp = test.get '/items/2'
     #   resp.body # => 'showing item: 2'
+    #
+    #   resp = test.post '/bar', 'name=YK&word=call'
+    #   resp.status # => 200
+    #
+    #   resp = test.post '/foo', JSON.dump(name: 'YK', created_at: Time.now)
+    #   resp.status # => 200
     class Test < Faraday::Adapter
       attr_accessor :stubs
 
@@ -181,7 +196,7 @@ module Faraday
           [(host.nil? || host == request_host) &&
             path_match?(request_path, meta) &&
             params_match?(env) &&
-            (body.to_s.size.zero? || request_body == body) &&
+            body_match?(request_body) &&
             headers_match?(request_headers), meta]
         end
 
@@ -222,6 +237,17 @@ module Faraday
           end
         end
 
+        def body_match?(request_body)
+          return true if body.to_s.size.zero?
+
+          case body
+          when Proc
+            body.call(request_body)
+          else
+            request_body == body
+          end
+        end
+
         def to_s
           "#{path} #{body}"
         end

lib/faraday/version.rb

@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
 module Faraday
-  VERSION = '2.3.0'
+  VERSION = '2.4.0'
 end

spec/faraday/adapter/test_spec.rb

@@ -373,5 +373,41 @@ RSpec.describe Faraday::Adapter::Test do
       it_behaves_like 'does not raise NotFound even when headers do not satisfy the strict check', '/with_user_agent', { authorization: 'Bearer m_ck', user_agent: 'My Agent' }
       it_behaves_like 'does not raise NotFound even when headers do not satisfy the strict check', '/with_user_agent', { authorization: 'Bearer m_ck', user_agent: 'My Agent', x_special: 'special' }
     end
+
+    describe 'body_match?' do
+      let(:stubs) do
+        described_class::Stubs.new do |stubs|
+          stubs.post('/no_check') { [200, {}, 'ok'] }
+          stubs.post('/with_string', 'abc') { [200, {}, 'ok'] }
+          stubs.post(
+            '/with_proc',
+            ->(request_body) { JSON.parse(request_body, symbolize_names: true) == { x: '!', a: [{ m: [{ a: true }], n: 123 }] } },
+            { content_type: 'application/json' }
+          ) do
+            [200, {}, 'ok']
+          end
+        end
+      end
+
+      context 'when trying without any args for body' do
+        subject(:without_body) { connection.post('/no_check') }
+
+        it { expect(without_body.status).to eq 200 }
+      end
+
+      context 'when trying with string body stubs' do
+        subject(:with_string) { connection.post('/with_string', 'abc') }
+
+        it { expect(with_string.status).to eq 200 }
+      end
+
+      context 'when trying with proc body stubs' do
+        subject(:with_proc) do
+          connection.post('/with_proc', JSON.dump(a: [{ n: 123, m: [{ a: true }] }], x: '!'), { 'Content-Type' => 'application/json' })
+        end
+
+        it { expect(with_proc.status).to eq 200 }
+      end
+    end
   end
 end